Betsy Sanchez, 14, had 70 per cent of her stomach removed after being bullied for her 95kg (15st) bulk.

In the two years since, she has gone on to shed 32kg (5st) and has taken up exercise for the very first time.

Betsy’s controversial operation was carried out by her uncle, Dr Guillermo Alvarez, who specialises in weight-loss surgery for adolescents.

The youngster, from Coahuila in Mexico, said: ‘When my uncle said he could make me thinner I was so excited. I was worried I was going to get so fat I’d end up bed-ridden. I can still have McDonald’s but much smaller portions – only two chicken nuggets and chips.

‘I’m much happier now and have lots of new friends.’

Betsy’s mother Ana, 39, added: ‘Diet and exercise didn’t work for Betsy, she was addicted to food.

‘I tried serving healthy food and cutting portions but Betsy was out of control. Only surgery would work.’